This invention relates to methods for testing the effect of various conditions on oligonucleotide arrays before, during of after production. The invention therefore relates to the fields of quality control in manufacturing and chemical assays.
New technology, called VLSIPS™, has enabled the production of chips smaller than a thumbnail that contain hundreds of thousands or more of different molecular probes. These techniques are described in U.S. Pat. No. 5,143,854, PCT WO 92/10092, and PCT WO 90/15070. Biological chips have probes arranged in arrays, each probe ensemble assigned a specific location. Biological chips have been produced in which each location has a scale of, for example, ten microns. The chips can be used to determine whether target molecules interact with any of the proves on the chip. After exposing the array to target molecules under selected test conditions, scanning devices can examine each location in the array and determine whether a target molecule has interacted with the probe at that location.
Biological chips are useful in a variety of screening techniques for obtaining information about either the probes or the target molecules. For example, a library of peptides can used as probes to screen for drugs. The peptides can be exposed to a receptor, and those probes that bind to the receptor can be identified.
Biological chips wherein the probes are oligonucleotides (“oligonucleotide arrays”) show particular promise. Arrays of nucleic acid probes can be used to extract sequence information from nucleic acid samples. The samples are exposed to the probes under conditions that allow hybridization. The arrays are then scanned to determine to which probes the sample molecules have hybridized. One can obtain sequence information by selective tiling of the probes with particular sequences on the arrays, and using algorithms to compare patterns of hybridization and non-hybridization. This method is useful for sequencing nucleic acids. It is also useful in diagnostic screening for genetic diseases or for the presence of a particular pathogen or a strain of pathogen.
The scaled-up manufacturing of oligonucleotide arrays requires application of quality control standards both for determining the quality of chips under current manufacturing conditions and for identifying optimal conditions for their manufacture. Quality control, of course, is not limited to manufacture of chips, but also to the conditions under which they are stored, transported and, ultimately, used.